Geologic structural breakdown

Inhomogeneity is quite naturally predicted to occur in this class of complexes. This is not only due to the different possible breakdown pathways in soils, sediments, etc., but is also due to the multiplicities of naturally occurring precursors in living organisms. For example, a number of known chlorophyll structures are shown in (23). The structural complexity is even more elaborate for the haems. Mixtures in geological media thus are to be expected. However, it should be pointed out that the amount of porphyrins from plant sources is overwhelming compared to that... 

From an eco-chemical aspect, this is probably the least interesting phase, since it is also the most immobile, because it includes silicate and oxide minerals and metal ions which are structurally incorporated in them, therefore that fraction of metals which practically cannot be mobilized from geological material in natural conditions. Concentrated mineral acids or their mixtures are usually used for breakdown of this crystal matrix. 

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